feat: modify fee rate fetching by adding complex logic

src/functions/bitcoin/bitcoin-functions.ts

@@ -21,7 +21,9 @@ import {
   BitcoinInputSigningConfig,
   BitcoinTransaction,
   BitcoinTransactionVectorOutput,
+  BlockData,
   FeeRates,
+  HistoricalFeeRate,
   PaymentTypes,
   UTXO,
 } from '../../models/bitcoin-models.js';
@@ -143,44 +145,94 @@ export function createTaprootMultisigPayment(
 }
 
 /**
- * Evaluates the fee rate from the bitcoin blockchain API.
+ * Fetches the last two blocks' fee rates from the bitcoin blockchain API.
  *
- * @returns The fee rate.
+ * @returns A promise that resolves to the last two blocks' median fee rates.
  */
-function checkFeeRate(feeRate: number | undefined): number {
-  if (!feeRate || feeRate < 2) {
-    return 2;
+export async function getLastTwoBlocksFeeRate(
+  bitcoinBlockchainAPIFeeURL: string
+): Promise<number[]> {
+  const dayFeeRateAPI = `${bitcoinBlockchainAPIFeeURL}/api/v1/mining/blocks/fee-rates/24h`;
+
+  const response = await fetch(dayFeeRateAPI);
+
+  if (!response.ok) {
+    throw new Error(`Bitcoin Blockchain Fee Rate Response was not OK: ${response.statusText}`);
   }
-  return feeRate;
+
+  const historicalFeeRates: HistoricalFeeRate[] = await response.json();
+
+  return historicalFeeRates.slice(historicalFeeRates.length - 2).map(rate => rate.avgFee_50);
 }
 
 /**
- * Fetches the fee rate from the bitcoin blockchain API.
+ * Fetches the current mempool block median fee rate from the bitcoin blockchain API.
  *
- * @returns A promise that resolves to the hour fee rate.
+ * @param bitcoinBlockchainAPIFeeURL
+ * @returns
  */
-export async function getFeeRate(
-  bitcoinBlockchainAPIFeeURL: string,
-  feeRateMultiplier?: number
+export async function getCurrentMempoolBlockFeeRate(
+  bitcoinBlockchainAPIFeeURL: string
 ): Promise<number> {
-  const response = await fetch(bitcoinBlockchainAPIFeeURL);
+  const mempoolBlocksAPI = `${bitcoinBlockchainAPIFeeURL}/api/v1/fees/mempool-blocks`;
+
+  const response = await fetch(mempoolBlocksAPI);
 
   if (!response.ok) {
     throw new Error(`Bitcoin Blockchain Fee Rate Response was not OK: ${response.statusText}`);
   }
 
-  let feeRates: FeeRates;
+  const currentBlockFeeRate: BlockData[] = await response.json();
 
-  try {
-    feeRates = await response.json();
-  } catch (error) {
-    throw new Error(`Error parsing Bitcoin Blockchain Fee Rate Response JSON: ${error}`);
+  return currentBlockFeeRate[0].medianFee;
+}
+
+/**
+ * Fetches the estimated fee rate from the bitcoin blockchain API.
+ *
+ * @returns A promise that resolves to the fastest fee rate.
+ */
+export async function getEstimatedFeeRate(bitcoinBlockchainAPIFeeURL: string): Promise<number> {
+  const estimatedFeeAPI = `${bitcoinBlockchainAPIFeeURL}/api/v1/fees/recommended`;
+
+  const response = await fetch(estimatedFeeAPI);
+
+  if (!response.ok) {
+    throw new Error(`Bitcoin Blockchain Fee Rate Response was not OK: ${response.statusText}`);
   }
 
-  const feeRate = checkFeeRate(feeRates.fastestFee);
-  const multipliedFeeRate = feeRate * (feeRateMultiplier ?? 1);
+  const feeRates: FeeRates = await response.json();
+
+  return feeRates.fastestFee;
+}
+
+/**
+ * Return the fee rate for the transaction.
+ *
+ * @returns A promise that resolves to the fee rate.
+ */
+export async function getFeeRate(
+  bitcoinBlockchainAPIFeeURL: string,
+  feeRateMultiplier?: number,
+  isRegtest = false
+): Promise<number> {
+  if (isRegtest) return 2;
+
+  const multiplier = feeRateMultiplier ?? 1;
+
+  const currentBlockFeeRate = await getCurrentMempoolBlockFeeRate(bitcoinBlockchainAPIFeeURL);
+  const lastTwoBlocksFeeRate = await getLastTwoBlocksFeeRate(bitcoinBlockchainAPIFeeURL);
+
+  const feeRates = lastTwoBlocksFeeRate.concat(currentBlockFeeRate);
+  const feeRateAverage = feeRates.reduce((a, b) => a + b) / feeRates.length;
+  const feeRateAverageMultiplied = Math.ceil(feeRateAverage) * multiplier;
+  console.log('Fee Rate Average Multiplied:', feeRateAverageMultiplied);
+
+  const estimatedFeeRate = await getEstimatedFeeRate(bitcoinBlockchainAPIFeeURL);
+  const estimatedFeeRateMultiplied = estimatedFeeRate * multiplier;
+  console.log('Estimated Fee Rate Multiplied:', estimatedFeeRateMultiplied);
 
-  return multipliedFeeRate;
+  return Math.max(feeRateAverageMultiplied, estimatedFeeRateMultiplied);
 }
 
 /**

src/models/bitcoin-models.ts

@@ -21,6 +21,27 @@ export interface FeeRates {
   minimumFee: number;
 }
 
+export interface BlockData {
+  blockSize: number;
+  blockVSize: number;
+  nTx: number;
+  totalFees: number;
+  medianFee: number;
+  feeRange: number[];
+}
+
+export interface HistoricalFeeRate {
+  avgHeight: number;
+  timestamp: number;
+  avgFee_0: number;
+  avgFee_10: number;
+  avgFee_25: number;
+  avgFee_50: number;
+  avgFee_75: number;
+  avgFee_90: number;
+  avgFee_100: number;
+}
+
 export interface PaymentInformation {
   fundingPayment: P2Ret | P2TROut;
   multisigPayment: P2TROut;

tests/unit/bitcoin-functions.test.ts

@@ -8,6 +8,7 @@ import {
   ecdsaPublicKeyToSchnorr,
   finalizeUserInputs,
   getFeeAmount,
+  getFeeRate,
   getFeeRecipientAddress,
   getInputIndicesByScript,
   getScriptMatchingOutputFromTransaction,
@@ -39,6 +40,12 @@ import {
 import { TEST_VAULT_UUID_1 } from '../mocks/ethereum.test.constants';
 
 describe('Bitcoin Functions', () => {
+  describe('getFeeRate', () => {
+    it('should return the fee rate in satoshis per byte', async () => {
+      const feeRate = await getFeeRate('https://mempool.space');
+      console.log(feeRate);
+    }, 30000);
+  });
   describe('getInputIndicesByScript', () => {
     it('correctly retrieves one input index by script', () => {
       const transaction = Transaction.fromPSBT(